PRINTED MICROWAVE SYSTEMS

The results of a theoretical and experimental investigation of the free modes that propagate on the strip transmission line are reported. A Fourier integral solution is obtained for the free modes. Since the integrals must be solved by numerical methods, approximate equations for the phase velocity, attenuation, and the characteristic impedance are developed for the "two-conductor " H-E mode. It is shown that a static assumption for the H-E mode is good only as a first approximation. In the course of the discussion, it is proved that the only free modes that may exist on any n-conductor system of arbitrary but constant cross section in homogeneous and simply connected space are TEM modes. Previously known methods for the determination of the guide wavelength and attenu-ation required that the standing waves of the strip transmission line be known. It was found that these could not be measured directly. Since precedent measuring methods were found to be inadequate, a new simple method for measuring the attenuation of any transmission line through a junction is presented. I I